X-ray tube.



E. W. CALDWELL.

X-RAY TUBE.

APPLICATION FILED IEB.12,1908.

1,056,401 Patented Mar. 18, 1913.

QVi/bweo-mo Moe Mot EUGENE w. CALDWELL, or NEW YORK, N. Y.

X-BAY TUBE.

Specification of Letters Patent.

Patented Mar. 18,1913.

Application filed February 12, 1908. Serial No. 415,474.

To all whom it may concern:

Be it known that I, EUGENE W. CALD- WELL, a citizen of the United States, and resident of the city, county, and State of New York, have made a certain new and useful Invent-ion Relating to X-Ray Tubes, of which the following is a specification, taken in connection with the accompanying drawings, forming part of the same.

This invention relates to X-ray tubes and relates especially to tubes in which the targetis formed with a recess which the cathode stream enters to impinge on the focal surface at the bottom of the recess to 15 generate X-rays which may be transmitted.

through the recess in substantially the opposite direction, the sides of the recess acting as a shield to intercept all the rays except those constituting the cone of X-rays utilized which may pass through a window in the cathode itself.

In the accompanying drawings showing illustrative embodiments of this invention in a somewhat diagrammatic way and in which the same reference numeral refers to similar parts in the several figures. Figur 1 is a longitudinal section of an X-ray tube and Fig. 2 is a similar sectional view of a modified form of tube.

As indicated in Fig. 1, the X-ray tube may comprise the bulb 1 and connected arms2, 3, and 4 of glass or other suitable material, the anode 5 being mounted withi in the arm 2and connected with the anode 35 terminal 6, as is usual. The target 7 may be formed of steel, electrolytic copper, silver or other high melting point material substantially opaque to the X-rays and connected with the target support 11 which may be mounted rigidly within the arm 4 in any desired way and connected with the target terminal 12. A suitable recess 9 may be formed in the target of a contour to normally embrace the cathode stream without substantial impingement of the stream on the sides of the recess, so that the cathode stream may impinge on the focal spot or surface 20 at the bottom of the recess. The target is preferably provided with a heavy lining 8 of platinum or other resistant material, and may, if desired, be formed with the shield extension 10 which approaches the cathode quite closely so as to more eifectually intercept any undesirable rays and increase the resistance between these parts. The recess may, if desired, be provided with a series of intercepting ridges 21 arranged annularly or otherwise so that the undesirable X-rays are intercepted on' i the faces of these ridges adjacent the focal spot so that any secondary X-rays generated are transmitted back into the recess and absorbed.

The cathode 15 having a concave working face may be mounted in proper position by the connector 14 which runs to the cathode 5 terminal 13, the cathode thus being mounted in the tube with suflicient rigidity for service requirements. If desired, the cathode may be provided with a window portlon transparent to the X-rays so as to allow the useful cone of X-rays from the target focus to be transmitted through the cathode. This may be accomplished by forming a suitable aperture or window 18 in the cathode or by forming the desired portion 16 of the cathode of thin aluminum or other material of such character and thickness as to be transparent to the X-rays or by using both ofthese expedients as is indicated in Fig. 1, itbeing, of course, desirable to provide the cathode with sufficient electrically conducting surface to properly generate the cathode stream. By using suitable impervious screen or backing 17 in 5 connection with the cathode and desired" portion of the cathode surface may be made opaque to the X-rays so that the X-ray cone 19 may be given the desired size.

As indicated in Fig. 2, the target 27 of similar material may be formed with a suitablerecess 29 provided with a suitable lining 28 of platinum or other material and provided with the focal surface 20 within the recess and preferablyadjacentthe bottom thereof. Thisrecess should, of course, be sufiiciently deep so that it will properly intercept the undesirable portion of the X-rays and may be of any desired shape so long as the cathode stream can enter the opening of the recess and impinge on the focal surface and the useful X-ray pencil pass out through this opening, undesirable portions of the X-rays generated being absorbed by the walls of the recess. The focal surface 20 is shown of limited area and the sides of the recess 29 may be of such shape as to closely embrace the cathode stream without substantial interception thereof. The cathode 30 may be similarly supported surface to by the connection it and may be formed of thin aluminum so as to be substantially transparent to the K-rays generated at the focus 20 and transmitted back through the cathode in substantially the opposite direction to the cathode stream entering the recess 29, the cathode being formed of such material as to act as a transparent window for the cone of rays 19.

Having described this invention in connection with a number of illustrative embodiments thereof, to the details of which disclosure the invention is not of course to be limited what is claimed as new and what is desired to be secured by Letters Patent is set forth in the appended claims:

1. The Til-ray tube having a target'provided with a deep recess of such shape as to substantially embrace the cathode stream entering said recess, there being a platinum lining in said recess formed with intercept ing ridges adjacent the focal surface at the bottom of said recess and a cathode having an impervious screen adjacent the shield extension of said target and having a window of material substantially transparent to A f-rays to allow the cone of X-rays from said focal surface to be transmitted through said cathode.

2. The Xray tube having a target provided with a deep recess having a resistant lining formed with intercepting ridges adjacent the focal surface in said recess and a cathode having a window transparent to the X-rays to allow the cone of Iii-rays from said focal be transmitted through said cathode.

3. The Xeray tube having a target provided with a deep recess having a resistant lining of such shape as to substantially embrace the cathode stream entering said recess, there being a focal surface at the bottom of said recess and a cathode mounted within said tube and having a window transparent to the X-ILtE/S to allow the cone of X-rays from said surface to be transmitted through said cathode.

4. The i i-ray tube having a glass body and target provided with a deep recess and a focal surface adjacent the bottom of said recess and a cathode mounted within said tube and having a window transparent to the Til-rays to intercept undesirable radiation and to allow the cone of X-rays from said focal surface to be transmitted through said cathode.

5. The arm tube having a glass body and a target provided with a deep recess and a focal surface within said recess to allow the cathode stream to enter said recess and impinge on said focal surface and to allow the useful pencil of X-rays generated to pass through said recess along substantially the same axis as said cathode stream there being a screen substantially impervious to X-rays within said tube and coiiperating with said target to intercept portions of the Xrays generated before striking said tube- 6. The X-ray tube having a glass body and target provided with a recess and with a focal surface within said recess and a cathode mounted within said tube to form a cathodestream entering said recess and impinging on said focal surface to generate T t-rays passing out through said recess along substantially the same axis as said cathode stream, said recess being provided with impervious material to intercept undesirable iii-rays generated.

7. The X-ray tube having a vitreous body and a target provided with a recess and with a focal surface adjacent the bottom of said recess and a cathode mounted within said tube having a portion transparent to the Eli-rays to create a cathode stream passing through said recess and impinging on said focal surface to generate K-rays passing back through said recess undesirable portions of the X-ravs generated being inter cepted by the walls of said recess.

8. The X-ray tube having a vitreous body and a target provided with a recess and with a focal surface within said recess, a cathode mounted within said tube having an impervious portion and having a window transparent to the X-rays to form a cathode str amentering said recess and impinging on said focal surface to generate X- rays passing out through said recess and through said cathode window undesirable portions of the X-rays generated being intercepted by the walls of said recess and by said screen.

9. The X-ray tube having a vitreous body and a target provided with a recess and a focal surface within said recess and a cathode mounted within said tube to cause the cathode stream to enter said recess and impinge on said focal surface and generate X-rays passing c t through said recess along substantially the same axis as the axis of the cathode stream.

10.. The X-ray tube having a vitreous body and a target provided with a recess and with a focal surface within said recess and a cathode mounted within said tube and having a window transparent to the X-rays to produce a cathode stream entering the opening of said recess and impinging on said focal surface to generate Iii-rays passing out through said opening and through said. cathode window.

11. The X-ray tube having a vitreous body and a target provided with a focal surface, a cathode mounted within said tube to coiiperate with said target and having a thickened edge portion substantially opaque to the X-rays and having a window -trans parent to the X-rays and intercepting undesirable radiation through which the useful X-rays from said target pass before striking said tube. 1 I

12. The X-ray tube having a vitreous body and a cathode mounted within the same and provided with a window substantially transparent to the X-rays to form a cathode stream, a target provided with a recess and having a focal surface substantially normal to the axis of the cathode stream impinging thereon to generate X- rays passing out through said recess along substantially the same axis as said cathode stream and the useful X-rays passiiig through said window before striking the body of said tube to intercept undesirable radiation.

13. The X-ray tube having a vitreous body and a cathode mounted within the same and provided with a window substan-' tially transparent to the X-rays to form a cathode stream, a target provided with a recess and having a focal surface substantially normal to the axis of the cathode stream impinging thereon to generate X- rays passing out through said recess along substantially the samejaxis as said cathode stream, undesirable portions of the X-rays generated being intercepted by the walls of said recess and the'useful X-rays passing through said window before striklng the body of said tube and to intercept undesirable radiation. i

14. The X-ray tube having a vitreous body and a cathode mounted within the same to form a cathode stream and a target having a focal surface substantially normal to the axis of the cathode stream impinging thereon to generate X-rays passing back substantially along the same axis as said cathode stream.

15. The X-ray tube having a vitreous body and a cathode mounted within the same to form a cathode stream, a target having a focal surface substantially normal to the axis of the cathode stream impinging thereon to generate X-rays passing back substantially along the same axis as said cathode stream and means Within said tube to intercept undesirable portions of the X-rays generated.

16. The X-ray tube having a vitreous body and a cathode mounted within the same, a target provided with a recess and having a focal surface within said recess to generate X-rays passing out of said recess along substantially the same axis as the entering cathode stream and a window mounted within said tube and substantially transparent X-rays and impervious to undesirable radiation through which the use ful X-rays of said tube.

' EUGENE W. CALDWELL. Witnesses:

HARRY L. DUNCAN, Jnssra B. KAY.

pass before striking the body 

